Explosive powered knock out punch



Jan. 22, 1963 R. L.. DAvls EXPLosIvE POWERED xNocK OUT PUNCH Filed Aug. 50, 1961 United States Patent O M 3,074,165 EXPLOSIVE POWERED KNCK OUT PUNCH Roy L. Davis, 1308 N. D St., Stockton, Calif. Filed Aug. 30, 1961, Ser. No. 134,999 4 Claims. (Cl. 30-228) This invention relates to a device for punching holes or openings in material such as metal, and more particularly to such a device which is operated or actuated by an explosive charge.

The object of the invention is to provide an explosively powered knock out punch which is a self-contained unit which requires no outside source of power for its operation.

Another object of the invention is to provide an explosive powered knock out punch which utilizes expanding gases from an exploded cartridge to furnish the power required to drive the cutting die, and whereinthe punch embodies a self aligning feature, the device being constructed so that the lower die is automatically brought into alignment with the upper die, and wherein a downward driving force on the self .aligning punch creates lateral movement of the lower die as a tapered point strikes a tapered shoulder in the lower die, the present invention utilizing in a novel manner magnetic forces to hold the parts in their proper position.

A further object is to provide an explosive powered knock out punch of the type stated that is rugged in structure and foolproof in operation and which is economical to manufacture and eicient to use.

These and other objects of the invention will become apparent from a reading of the following specification and claims, together with the accompanying drawings,

wherein like parts are referred to and indicated by like reference characters and wherein:

FIGURE l is a longitudinal vertical sectional view taken through the explosive powered knock out punch of the present invention, and showing the position of the parts before the cartridge is exploded or detonated.

IGURE 2 is a ,fragmentary sectional view similar to FIGURE l, but showing an intermediate position of the parts and illustrating the piston moving down and the punch engaging the aperture in the lower die to center the lower die, the lower die in FIGURE l being shown in an olf-center position.

FIGURE 3 is a fragmentary sectional view showing vthe upper die and its associated parts all the Way down and punching or cutting the hole in the metal or other material being worked, and FIGURE 3 also showing the exhaust ports uncovered so that the exhaust gases from the detonated cartridge can pass outwardly therethrough.

FIGURE 4 is a sectional view taken on the line 4 4 of FIGURE 3.

FIGURE 5 is a bottom plan view showing the base and upper die.

FIGURE 6 is a top plan view of the lower die.

Referring in detail to the drawings, the numeral 10 indicates the explosive powered knock out punch or tool of the present invention in its entirety, and the tool 10 ernbodies a body member which is indicated generally by the numeral 25, and the body member 25 includes a lower section 11 as well as an upper section 12, and the upper section 12 is of reduced size. The upper section 12 is provided with a recess 13 therein, FIGURE 1, and the numeral 14 indicates a plug which is removable from the recess 13, and the plug 14 is adapted to be threaded into the recess as for example at the point 15.

The plug 14 is provided with a vertically disposed longitudinally extending bore 16, and the bore 16 is shown to comprise an upper section 17 of increased size and a lower section 18 of reduced size, and there is deined between the sections 17 and 18 a shoulder 19. The nu- 3,@74165 Patented Jan. 22, 19$3 meral 20 indicates a movable firing pin which includes a shank 21, and the upper end of the shank 21 projects above the top of the body member 25, whereby this upper projecting end can be struck by a hammer or the like when the tool 10 is to be actuated. The lower end of the iring pin 20 is pointed as at 22, and there is provided on the shank 21 a circular flange 23. The numeral 24 indicates a coil spring which is circumposed on the shank 21, and the coil spring 24 is interposed between the flange 23 and the shoulder 19.

There is provided in the body member 25 below the recess 13 an opening 26, and the numeral 27 indicates a cartridge which is adapted lto be arranged in the opening 26. Arranged below the opening 26 is a space 28, and a plurality of inclined passageways 29 are formed in the body member 25, the upper ends of the passageways 29 communicating with the space 2S. The numeral 30 indicates an inner chamber within the lowerA portion of the body member 25, and the lower ends of the passageway 29 communicate with the chamber 30. The side wall of the body member 25 is provided with a plurality of spaced apart ports 31 which function as exhaust ports so that the exhaust gases can escape through these ports 31 as later described in this application.

Movably mounted in the chamber 36 is a reciprocable plunger or piston 32, and the piston 32 includes a head 33 which has an annular groove 34 in the lower surface thereof. The head 32 further includes a depending support portion 35 which is threaded externally, and the support portion 35 is provided with an internally threaded opening 36. The numeral 37 indicates a pin or punch which has its upper end threaded for threadedly engaging the threaded opening 36 in the support portion 35 of the head 32, and the lower end of the punch 37 is tapered to provide a generally pointed lower end as indicated by the numeral 38.

The numeral 39 indicates an upper die which includes an internally threaded cylindrical sleeve 40 which threadedly engages the support portion 35, FIGURE l, and the upper die 39 further includes a bottom wall 41 which has a circular cutting edge 42 depending from its outer periphery. The wall 41 is provided with a central opening 43 for the projection therethrough of the punch 37.

The numeral 44 indicates a base which includes an externally threaded section 45 that -threadedly engages the lower inner portion of the body member 16, and the base 44 further includes an outer lower recessed portion 46 which denes an annular shoulder 47, and a plurality of magnets 48 are suitably secured in the recessed portion 46.

In the drawings, the numeral 49 indicates the work being punched which may be of a suitable metal, and the work piece 49 is provided with a hole or opening 50 which may be formed in any suitable manner, as for example by means of a drill, and according to the present invention a circular section of material as indicated by the numeral 52 is adapted to be punched out so as to leave or provide in the work piece 49 an enlarged smooth circular opening as indicated by the numeral 51, FIG- URE 3.

The numeral 54 indicates a lower die which includes a wall portion 55 that has an annular recess or groove 56 in the upper surface thereof for receiving the cutting edge 42 of the upper die 39, when the parts are in the position of FIGURE 3. There is also provided a coil spring 57 which is arranged so that its upper end engages the groove 34 in the piston 32, and the lower end of the spring 57 abuts or engages the base 44 so that the spring 57 will function as a return spring to move the parts back to the position of FIGURE 1 from the position shown in FIGURE 3 after the explosive gases have exhausted up through the ports 31.

The upper outer surface of the lower die `dal is provided with a recessed portion 58, and magnets 59 are suitably secured in the recessed portion 5S, and these magnets S9 `are adapted to coact with the magnets 4S.

There is provided in the lower die S4 a central Ibore or opening 60 which is shown to comprise a lower cylindrical section 61 and an upper daring or tapered section y62, land this opening 60 is adapted to receive the punch 37, as for example as shown in FIGURES 2 and 3.

The plug is adapted to be provided with small recesses 63 whereby a suitable tool can be arranged in engagement with such recesses in ord-er to facilitate the unscrewing or removal or insertion of the plug le in the recess t3.

From the foregoing, it -is apparent that there has been provided an explosive operated punch or tool, and wherein with the parts arranged as shown in the drawings, it will be seen that a cartridge such as the cartridge 27 is adapted to be positioned in the opening 26, it being understood that the plug is first removed from the recess I3 in order :to gain access to the opening 26 in which the cartridge 27 is seated. The plug 14 is threaded into the recess d3 after the cartridge 27 is positioned in the opening 26, fand then with the work pieceisuch as the work piece 49 between the base 44- and the lower die 51.1, it will be seen that the piston 32 will be in a raised position due to the force of the return spring 57. To operate the present invention, the upper projecting end of the tiring pin 26 is adapted to be actuated in any suitable manner, as for example by striking the upper end of the pin 2d with a hammer or the like, and this causes the lower pointed end 22 ofthe pin 2li to detonate the cartridge 27, and the spring 24 will then return the pin 2l) to its raised position as shown in FIGURE 1, When the cartridge 27 is detonated, the explosive gases from the cartridge 27 will enter the space 2S below the opening 26, and these explosive gases will liow or pass through the downwardly' inclined passageways 29 and into the chamber 3! so that these expandmg gases will quickly push or move the piston 3?. downwardly to compress the coil spring 57 so that the parts will move from a position such as that shown in FIGURE l to a position such as that shown in FIGURE 2. It 1S t0 be noted that at this time the ports 3l are closed off s0 that the explosive gases cannot escape through these POrts 31, FIGURES l and 2. As the piston 32 moves downwardly in the chamber 3i), the punch or Vpin 37 will move through the opening V50 in the metal or work piece 49, and the tapered lower end 3S of the punch 37 will engage the daring or tapered shoulder portion 62 of the opening d@ and assuming for example that the base 64 is (a-centered as shown in FIF- URE l, this movement of the punch 37 into the opening 60 will have the eitect of shifting the base 64 so that the base 64 will be centered as for example as shown in FIGURE 2.

As the piston 32 continues to move downwardly, the upper die 39 will move downwardly since the die 39 is connected to the piston 32, and as the die 39 moves downwardly, its cutting edge 42 will engage the work piece 9 so that an opening such as the opening Si will be formed or punched in the material 59 and a circular section 52 will be punched out of the work piece 49.

The magnets i8 on the lower portion of the bese se lcoact with the magnets 59 on the upper portion of the lower die 54 whereby the lower die will be maintained v'in its proper position, and these magnets 4S and 59 are :arranged in such a manner that their polarity will cause :an attractive force to be exerted between the magnets vso that the lower die 54 will be retained in position. The Vgroove S6 provides clearance space for receiving the cutting edge 42 when the parts are in the position of FIGURE 3, and the parts assume the position of FIGURE 3 after they move from the position shown in FIGURE 2.

The parts can be made of any suitable material and in (different shapes or sizes.

Initially before the cartridge .27 is detonated or set oit,

the parts are in the position of FIGURE l, and after the cartridge 27 is detonated by actuating the tiring pin 2t), the piston 32 and associated parts move to a position such as that shown in FIGURE 2, and from the position shown in FIGURE 2 the parts move nally to the position shown in FIGURE 3 which illustrates therstep of punching out the openings such as the openings 51 in the work piece 49. With the parts in the position of FIGURE 3, the piston 32 is in lowered position so that the ports 31 are uncovered so that the exhaust gases can flow or pass out through these openings or ports 31 and into the atmosphere whereby the spring 57 will be able to return the parts from the position shown in FIGURE 3 to a position such as that shown in FIGURE l so that the tool can be used again in the same manner as previously described.

The magnets 43 are preferably permanent magnets of north polarity, while the magnets 59 are permanent magnets such as permanent magnets of south polarity. FIG- URE l shows the lower die 5ft off center or out of alignment, and as shown in the drawings, as the punch 37 moves downwardly and has its tapered portion 38 engage the aring section 62, the lower die S4 will be shifted or moved into its proper aligned position. The angular arrangement of these parts determines the distance that the lower die may be out of alignment and still be moved into its proper position upon actuation of the tool. In actual practice the lower die 54 is adapted to be placed by hand as close to the center of the tool as possible, but the parts will still cut accurately even it the lower die is od center, since the self aligning punch 37 will push the die 54 into `'alignment before the cut starts, and this is illustrated in FIGURE 2.

Minor changes in shape, size and rearrangement of details coming within the field of invention claimed may be resorted to in actual practice, if desired.

What is claimed is:

l. In a device of the 'character described, a body member including a lower section and an upper section of reduced size, there being a recess in said upper section, a plug threadedly mounted in said recess, there being a bore in said plug which includes lirst and second portions of dilerent sizes dening -a shoulder therebetween, a tiring pin movably mounted in said bore and said tiring pin including a shank having a lower pointed end, a circular llange on said shank, a coil spring circumposed on said shank and said coil spring being interposed between said flange and shoulder, there being an opening in said body member below said recess, a carriage snugly seated in said opening for engagement by the pointed end of said pin, there being a space in said body member below said opening, said body member having a plurality of inclined passageways which have their upper ends communicating with said space, said body member having an inner chamber which communicates with the lower ends of the passageways, said body member having a plurality of spaced apart exhaust ports which communicate withV said chamber, a piston movably mounted in said chamber and said piston including a depending support portion, a punch having its upper end threadedly engaging said support portion, the lower end of the punch tapering to a point, a movable upper die including a sleeve threadedly engaging said support portion, said die further including a bottom wall provided with a central aperture, a circular cutting edge depending from the outer periphery of said bottom wall, a base including an externally threaded section threadedly engaging the lower inner portion of the body member, said base having a lower outer recessed portion, magnets secured in said recessed portion, a lower die including a wall portion having an outer upper recessed section, magnets secured in said recessed section, said lower die including a central aperture for selectively receiving said punch, said last named aperture including a lower cylindrical section and an upper flaring defining a shouldered surface, there being an annular recess in the upper surface of the lower die for selectively receiving the cutting edge of the upper die, and a return spring interposed between said base and piston.

2. The structure as dened in claim l wherein the material to be punched is interposed between the magnets of the lower die, and the magnets of the base.

3. A device of the character described comprising a body member, means for supporting a cartridge in said body member, a spring pressed firing pin having a portion thereof projecting up above the top of the body member, the lower end of the firing pin adapted to engage and detonate the cartridge, a piston slidably mounted in said body member, passageway means for conveying gases from the cartridge to the piston, a punch carried by said piston, a base mounted in the lower end of the body member, a return spring interposed between said base and piston, an upper die connected to said piston, a lower die adjustably mounted below said upper die, coacting magnetic means on said base and lower die, and said lower die having an aperture therein for receiving said punch.

4. A device of the character described comprising a body member, means for supporting a cartridge in said body member, a spring pressed firing pin having a portion thereof projecting up above the top of the body member, the lower end of the firing pin adapted to en- -gave and detonate the cartridge, a piston slidably mounted in said body member, passageway means for conveying gases from the cartridge tothe piston, a punch carried by said piston, a base mounted in the lower end of the body member, a return spring interposed between said base and piston, an upper die connected to said piston, a lower die adjustably mounted below said upper die, coacting magnetic means on said base and lower die, and said lower die having an aperture therein for receiving said punch, the lower end of the punch having a tapering pointed formation, said aperture including a lower cylindrical section and an upper aring surface which denes a shouldered portion.

No references cited. 

1. IN A DEVICE OF THE CHARACTER DESCRIBED, A BODY MEMBER INCLUDING A LOWER SECTION AND AN UPPER SECTION OF REDUCED SIZE, THERE BEING A RECESS IN SAID UPPER SECTION, A PLUG THREADEDLY MOUNTED IN SAID RECESS, THERE BEING A BORE IN SAID PLUG WHICH INCLUDES FIRST AND SECOND PORTIONS OF DIFFERENT SIZES DEFINING A SHOULDER THEREBETWEEN, A FIRING PIN MOVABLY MOUNTED IN SAID BORE AND SAID FIRING PIN INCLUDING A SHANK HAVING A LOWER POINTED END, A CIRCULAR FLANGE ON SAID SHANK, A COIL SPRING CIRCUMPOSED ON SAID SHANK AND SAID COIL SPRING BEING INTERPOSED BETWEEN SAID FLANGE AND SHOULDER, THERE BEING AN OPENING IN SAID BODY MEMBER BELOW SAID RECESS, A CARRIAGE SNUGLY SEATED IN SAID OPENING FOR ENGAGEMENT BY THE POINTED END OF SAID PIN, THERE BEING A SPACE IN SAID BODY MEMBER BELOW SAID OPENING, SAID BODY MEMBER HAVING A PLURALITY OF INCLINED PASSAGEWAYS WHICH HAVE THEIR UPPER ENDS COMMUNICATING WITH SAID SPACE, SAID BODY MEMBER HAVING AN INNER CHAMBER WHICH COMMUNICATES WITH THE LOWER ENDS OF THE PASSAGEWAYS, SAID BODY MEMBER HAVING A PLURALITY OF SPACED APART EXHAUST PORTS WHICH COMMUNICATE WITH SAID CHAMBER, A PISTON MOVABLY MOUNTED IN SAID CHAMBER AND SAID PISTON INCLUDING A DEPENDING SUPPORT PORTION, A PUNCH HAVING ITS UPPER END THREADEDLY ENGAGING SAID SUPPORT PORTION, THE LOWER END OF THE PUNCH TAPERING TO A POINT, A MOVABLE UPPER DIE INCLUDING A SLEEVE THREADEDLY ENGAGING SAID SUPPORT PORTION, SAID DIE FURTHER INCLUDING A BOTTOM WALL PROVIDED WITH A CENTRAL APERTURE, A CIRCULAR CUTTING EDGE DEPENDING FROM THE OUTER PERIPHERY OF SAID BOTTOM WALL, A BASE INCLUDING AN EXTERNALLY THREADED SECTION THREADEDLY ENGAGING THE LOWER INNER PORTION OF THE BODY MEMBER, SAID BASE HAVING A LOWER OUTER RECESSED PORTION MAGNETS SECURED IN SAID RECESSED PORTION, A LOWER DIE INCLUDING A WALL PORTION HAVING AN OUTER UPPER RECESSED SECTION, MAGNETS SECURED IN SAID RECESSED SECTION, SAID LOWER DIE INCLUDING A CENTRAL APERTURE FOR SELECTIVELY RECEIVING SAID PUNCH, SAID LAST NAMED APERTURE INCLUDING A LOWER CYLINDRICAL SECTION AND AN UPPER FLARING DEFINING A SHOULDERED SURFACE, THERE BEING AN ANNULAR RECESS IN THE UPPER SURFACE OF THE LOWER DIE FOR SELECTIVELY RECEIVING THE CUTTING EDGE OF THE UPPER DIE, AND A RETURN SPRING INTERPOSED BETWEEN SAID BASE AND PISTON. 